This is you and your build, chief. Many have dropped AV's and GM's with less effort or more effort than other AT's.
just as with the other AT's, MM's have primaries and secondaries that are not that great, and combos that don't mesh. Beasts for example is the worst performing MM primary so if you are shooting for a THEME, then understand that just like any other AT you may have to make sacrifices to go for a THEME over POWER.